1. Field of the Invention
The invention relates generally to constant volume mobility joints particularly suited for use in interconnecting adjacent segments of an hermetically sealed pressure suit such as the so-called spacesuit.
2. Description of the Prior Art
Pressure suits, often referred to as diving suits, have long been employed for protecting divers at substantially great depths in positive pressure environments found beneath the sea. With man's entry into the exploration of celestial space, it has been found that pressure suits also have utility in negative pressure environments, such as often are found beyond the earth's atmosphere. Of course, pressure suits designed for use in the positive pressures of undersea environments are extremely bulky and generally of substantial mass, as typified by the diving suit shown in U.S. Pat. No. 2,034,637. Consequently, due to the bulk and mass of diving suits, it has been found that they generally are not suitable for use in the exploration of celestial space.
In the relatively recent past, numerous attempts have been made to provide pressure suits particularly suited for use in celestial space environments, commonly referred to as spacesuits. Among such suits are those disclosed in U.S. Pat. No. 3,405,406, which issued Oct. 15, 1968, and U.S. Pat. No. 3,636,564, which issued to the instant inventor Jan. 25, 1972.
Generally speaking, spacesuit mobility is of utmost concern to the wearer, since a lack of mobility may seriously impair the success of a mission. In the past, joints of hard spacesuits have utilized molded convolutes, toroidal structures, link structures, multiple bearings, and gathered and pleated fabrics.
As can be appreciated by those familiar with the design and fabrication of pressure suits for use in celestial space environments, the joints of the suits of the prior art typically exhibit torque which increases proportionally with internal suit pressure. Additionally, such joints are not neutrally stable throughout their range defined by the limits of their throw. Consequently, the motion of a wearer of such a suit often is impaired, due to the effects of the torque, with attendant reduction in or even loss of mission capabilities. Additionally, such joints normally are not neutrally stable throughout their range of motion. For example, as is discussed in U.S. Pat. No. 3,242,499, it has been found that an unrestrained bellows tubing will normally elongate and straighten when subjected to internal pressures which exceed the external pressures, and will, therefore, exhibit forces which oppose forces acting to flex the bellows joints. This characteristic of a bellows tubing may be of little consequence where bending forces are high, but where unrestricted flexibility is desired, such as in a spacesuit, use of typical bellows sections generally tends to be impractical. These and other difficulties, such as maintaining the integrity of the suit under pressure for long periods, are encountered when approaching the problem of providing for increased mobility through a use of the joints suggested by the prior art.
It is therefore the general purpose of the instant invention to provide in an hermetically sealed spacesuit improved mobility joints which are characterized by low torques, low leakage and high reliability throughout the full throw of the bending range thereof.